Hydraulic Turbines and Jets MCQ

51. A pelton turbine develops a power of 2500 kW at 200 rpm under a net head of 400m. Calculate its approximate specific speed.

  1. 9
  2. 3
  3. 8
  4. 6
Answer
Answer. d

52. The unit power Pu of a turbine developing power P under head H is equal to

  1. P/H2.5
  2. P/H0.5
  3. PH1.5
  4. P/H1.5
Answer
Answer. d

53. In all reaction turbines, for maximum efficiency,

  1. the velocity of swirl at the entrance must be zero
  2. the velocity of flow at outlet must be zero
  3. the velocity of swirl at the outlet must be zero
  4. the velocity of flow at entrance must be zero
  5. temperature of fluid must remain constant
Answer
Answer. c

54. A turbine develops 500 kW power under a head of 100 m at 200 rpm. What would be its normal speed under a head of 81 m?

  1. 250 rpm
  2. 670 rpm
  3. 550 rpm
  4. 900 rpm
  5. 180 rpm
Answer
Answer. e

55. ___________ is a tangential-flow impulse turbine.

  1. Pelton wheel turbine
  2. Kaplan turbine
  3. Francis turbine
  4. Propeller turbine
  5. Draft tube
Answer
Answer. a

56. In a Francis turbine, the water

  1. flows out through a closed draft tube
  2. flows out openly
  3. either flows out through a draft tube or openly depending on the type of design
  4. neither flows out openly nor through a closed draft tube
Answer
Answer. a

57. Name the ratio of power available at the shaft of a turbine to the power delivered by water to the runner.

  1. volumetric efficiency
  2. overall efficiency
  3. mechanical efficiency
  4. hydraulic efficiency
Answer
Answer. c

58. Governing of a turbine means

  1. the head is kept constant under all conditions of working
  2. the speed is kept constant under all conditions of working
  3. the discharge is. kept constant under all conditions of working
  4. the frictional loss is kept constant under all conditions of working
Answer
Answer. b

59. Which of the following statement(s) is/are incorrect?

  1. A turbine is called impulse turbine if at the inlet of the turbine total energy is only kinetic energy
  2. A turbine is called reaction turbine if at the inlet of the turbine the total energy is kinetic energy and pressure energy
  3. The inward flow reaction turbine having radial discharge at outlet is known as Kaplan turbine
  1. Only iii
  2. Only i
  3. ii and iii
  4. i and ii
Answer
Answer. a

60. To generate 8100 kW under a head of 81 m while working at a speed of 540 r.p.m., what type of turbine is suitable?

  1. Pelton
  2. Francis
  3. Bulb
  4. Kaplan
Answer
Answer. b
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